Antimony mercaptides have been proposed as stabilizers for vinyl halide resins to guard against degradation by heat during molding and working of the resins into useful articles. Prior art patents which disclose such antimony organic sulfur-containing compounds and their utility as stabilizers include U.S. Pat. Nos. 2,680,726; 2,684,956; 3,340,285; 3,399,220; 3,466,261 and 3,530,158. U.S. Pat. No. 3,887,508 to Dieckmann is directed to improvements in the utilization of antimony organic sulfur-containing compounds in combination with metal carboxylates. As also described in U.S. Pat. No. 3,919,168 to Dieckmann, certain metal phosphates can be combined with antimony compounds to achieve long term heat stability improvements in vinyl halide resins. U.S. Pat. Nos. 4,029,618 and 4,158,640 to Dieckmann further disclose synergistic heat stabilizer compositions of such antimony compounds as stabilizers and ortho-dihydric phenols.